U.S. patent application number 12/628189 was filed with the patent office on 2010-06-24 for linear deposition source.
This patent application is currently assigned to VEECO INSTRUMENTS, INC.. Invention is credited to Richard Charles Bresnahan, Chad Conroy, Jacob Allan Dahlstrom, David William Gotthold, John Charles Patrin, Scott Wayne Priddy.
Application Number | 20100159132 12/628189 |
Document ID | / |
Family ID | 42194336 |
Filed Date | 2010-06-24 |
United States Patent
Application |
20100159132 |
Kind Code |
A1 |
Conroy; Chad ; et
al. |
June 24, 2010 |
Linear Deposition Source
Abstract
A deposition source includes a plurality of crucibles that each
contains a deposition material. A heat shield provides at least
partial thermal isolation for at least one of the plurality of
crucibles. A body is included with a plurality of conductance
channels. An input of each of the plurality of conductance channels
is coupled to an output of a respective one of the plurality of
crucibles. A heater increases a temperature of the plurality of
crucibles so that each crucible evaporates the deposition material
into the plurality of conductance channels. An input of each of a
plurality of nozzles is coupled to an output of one of the
plurality of conductance channels. Evaporated deposition materials
are transported from the crucibles through the conductance channels
to the nozzles where the evaporated deposition material is ejected
from the plurality of nozzles to form a deposition flux.
Inventors: |
Conroy; Chad; (Stillwater,
MN) ; Priddy; Scott Wayne; (Saint Loius Park, MN)
; Dahlstrom; Jacob Allan; (Cottage Grove, MN) ;
Bresnahan; Richard Charles; (Cottage Grove, MN) ;
Gotthold; David William; (Lino Lakes, MN) ; Patrin;
John Charles; (Chanhassen, MN) |
Correspondence
Address: |
RAUSCHENBACH PATENT LAW GROUP, LLP
P.O. BOX 387
BEDFORD
MA
01730
US
|
Assignee: |
VEECO INSTRUMENTS, INC.
Plainview
NY
|
Family ID: |
42194336 |
Appl. No.: |
12/628189 |
Filed: |
November 30, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61156348 |
Feb 27, 2009 |
|
|
|
61138932 |
Dec 18, 2008 |
|
|
|
Current U.S.
Class: |
427/248.1 ;
118/726 |
Current CPC
Class: |
Y02E 10/541 20130101;
C23C 14/243 20130101; Y02P 70/521 20151101; Y02P 70/50 20151101;
C23C 14/26 20130101; C23C 14/562 20130101 |
Class at
Publication: |
427/248.1 ;
118/726 |
International
Class: |
C23C 16/44 20060101
C23C016/44; C23C 16/00 20060101 C23C016/00 |
Claims
1. A deposition source comprising: a) a plurality of crucibles for
containing deposition material; b) a body comprising a plurality of
conductance channels, an input of each of the plurality of
conductance channels being coupled to an output of a respective one
of the plurality of crucibles; c) a heater that is positioned in
thermal communication with the plurality of crucibles and the
plurality of conductance channels, the heater increasing a
temperature of the plurality of crucibles so that each of the
plurality of crucibles evaporates the deposition material into the
plurality of conductance channels; d) a heat shield that provides
at least partial thermal isolation for at least one of the
plurality of crucibles; and e) a plurality of nozzles, an input of
each of the plurality of nozzles being coupled to an output of one
of the plurality of conductance channels, evaporated deposition
materials being transported from the plurality of crucibles through
the plurality of conductance channels to the plurality of nozzles
where the evaporated deposition material is ejected from the
plurality of nozzles to form a deposition flux.
2. The deposition source of claim 1 wherein at least some of the
plurality of crucibles comprises an inner crucible positioned
inside an outer crucible.
3. The deposition source of claim 1 wherein the plurality of
crucibles comprises a first crucible containing Cu, a second
crucible containing In, and a third crucible containing Ga.
4. The deposition source of claim 1 wherein each of the plurality
of crucibles contains the same deposition material.
5. The deposition source of claim 1 wherein the heater comprises at
least one of an RF induction heater, a resistive heater, and an
infrared heater.
6. The deposition source of claim 1 wherein the heater comprises a
plurality of individually controllable heaters wherein a respective
one of the plurality of heaters is in thermal communication with a
respective one each of the plurality of crucibles.
7. The deposition source of claim 1 wherein the heater raises
temperatures of each of the plurality of conductance channels above
the condensation point of the deposition materials.
8. The deposition source of claim 1 wherein the heater controls a
temperature of one of the plurality of conductance channels
relative to another one of the plurality of conductance
channels.
9. The deposition source of claim 1 wherein the heat shield
provides at least partial thermal isolation for at least one of the
plurality of conductance channels.
10. The deposition source of claim 1 wherein the heat shield
comprises a plurality of heat shielding tiles.
11. The deposition source of claim 1 wherein the heat shield
comprises a plurality of layers of heat shielding material.
12. The deposition source of claim 1 wherein the heat shield is
attached to the body with an expansion link.
13. The deposition source of claim 1 wherein the heat shield
comprises at least one surface with a low emissivity.
14. The deposition source of claim 1 wherein the heat shield
comprises a plurality of heat shields wherein a respective one of
the plurality of heat shields surrounds a respective one of the
plurality of crucibles.
15. The deposition source of claim 1 wherein the heat shield
surrounds the plurality of conductance channels.
16. The deposition source of claim 1 wherein the heat shield is
positioned so that at least one of the plurality of conductance
channels is at a different operating temperature than at least one
other of the plurality of conductance channel.
17. The deposition source of claim 1 wherein a spacing of the
plurality of nozzles is non-uniform.
18. The deposition source of claim 1 wherein a spacing of the
plurality of nozzles is closer proximate to an edge of the body
than a spacing of the plurality of nozzles proximate to a center of
the body.
19. The deposition source of claim 1 wherein a spacing of the
plurality of nozzles is chosen to achieve substantially uniform
deposition material flux.
20. The deposition source of claim 1 wherein a spacing of the
plurality of nozzles is chosen to increase utilization of
deposition material.
21. The deposition source of claim 1 wherein a spacing of the
plurality of nozzles is chosen to provide a desired overlap of
deposition flux from the plurality of nozzles.
22. The deposition source of claim 1 wherein at least one of the
plurality of nozzles is positioned at an angle relative to a normal
angle to a top surface of the plurality of conductance channels
that is chosen to provide a desired overlap of deposition flux from
the plurality of nozzles.
23. The deposition source of claim 1 wherein at least one of the
plurality of nozzles comprises an aperture that is shaped to pass a
non-uniform deposition flux.
24. The deposition source of claim 1 wherein at least one of the
plurality of nozzles comprises a low emissivity coating.
25. The deposition source of claim 1 wherein at least one of the
plurality of nozzles is formed of a material having a thermal
conductivity that results in a uniform operating temperature,
thereby reducing spitting of deposition materials from the
plurality of nozzles.
26. The deposition source of claim 1 wherein at least one of the
plurality of nozzles comprises a tube that is positioned proximate
to the conductance channel, the tube restricting the amount of
deposition material supplied to the corresponding nozzle.
27. The deposition source of claim 26 wherein a length the tube is
chosen to achieve a predetermined deposition flux through a
corresponding one of the plurality of nozzles.
28. The deposition source of claim 1 wherein at least one of the
plurality of nozzles comprises a tube that is positioned at least
partially into the conductance channel, the tube restricting the
amount of deposition material supplied to the corresponding
nozzle.
29. The deposition source of claim 1 wherein at least two of the
plurality of nozzles comprise a tube that restricts an amount of
material supplied to corresponding nozzles, a length of the tube
corresponding to one of the plurality of nozzles being different
from a length of the tube corresponding to at least one other of
the plurality of nozzles.
30. The deposition source of claim 1 wherein at least two of the
plurality of nozzles comprise a tube that restricts an amount of
material supplied to corresponding nozzles, a geometry of the tube
corresponding to one of the plurality of nozzles being different
from a geometry of the tube corresponding to at least one other of
the plurality of nozzles.
31. The deposition source of claim 1 wherein a top of at least one
of the plurality of nozzles extends above the plurality of
conductance channels.
32. The deposition source of claim 1 wherein a top of at least one
of the plurality of nozzles extends below the plurality of
conductance channels.
33. The deposition source of claim 1 further comprising fluid
cooling channels positioned proximate to at least one edge of the
body.
34. A method of generating deposition flux, the method comprising:
a) heating a plurality of crucibles that each contain a deposition
material so that each of the plurality of crucibles evaporate
deposition material that transports through one of a plurality of
conductance channels in a body; and b) transporting the evaporated
deposition material from each of the plurality of conductance
channels to one of the plurality of nozzles, the plurality of
nozzles passing evaporated deposition material, thereby forming a
deposition flux.
35. The method of claim 34 further comprising transporting the
evaporated deposition material from each of the plurality of
conductance channels through a respective one of a plurality of
tubes to a respective one of the plurality of nozzles.
36. The method of claim 35 further comprising selecting dimensions
of at least one of the plurality of tubes to achieve a uniform
deposition flux from the plurality of nozzles.
37. The method of claim 35 further comprising selecting dimensions
of at least one of the plurality of tubes to achieve a high
deposition material utilization.
38. The method of claim 34 further comprising independently
controlling a temperature of at least some of the plurality of
crucibles and the plurality of conductance channels.
39. The method of claim 34 further comprising shielding heat
generated by at least one of the plurality of crucibles to control
a temperature of at least one crucible relative to a temperature of
at least one other crucible.
40. The method of claim 34 further comprising shielding heat
generated by at least one of the plurality of conductance channels
to control a temperature of at least one conductance channel
relative to a temperature of at least one other conductance
channel.
41. The method of claim 34 further comprising providing space for
thermal expansion of heat shielding material proximate to at least
one of the plurality of crucibles and the plurality of conductance
channels.
42. A deposition source comprising: a) a crucible that contains at
least one deposition material; b) a body comprising a plurality of
conductance channels that are coupled to the crucible; c) a heater
that is positioned in thermal communication with the crucible, the
heater increasing a temperature of the crucible so that the
crucible evaporates the at least one deposition material into the
plurality of conductance channels; d) a heat shield that provides
at least partial thermal isolation for the crucible; and e) a
plurality of nozzles that are coupled to the plurality of
conductance channels, evaporated deposition materials being
transported from the crucible through the plurality of conductance
channels to the plurality of nozzles where the evaporated
deposition material is ejected from the plurality of nozzles to
form a deposition flux.
43. The deposition source of claim 42 wherein the crucible
comprises a plurality of partially isolated sections, each of the
partially isolated sections being dimensioned for positioning one
of a plurality of deposition materials.
44. The deposition source of claim 43 wherein at least two of the
plurality of partially isolated sections contain different
deposition materials.
45. The deposition source of claim 43 wherein an input of each of
the plurality of conductance channels is positioned proximate one
of the plurality of partially isolated sections.
46. The deposition source of claim 43 wherein the heat shield
provides thermal isolation that controls a temperature of one
section of the crucible relative to another section of the
crucible.
47. The deposition source of claim 42 wherein the heater is
positioned in thermal communication with at least one of the
plurality of conductance channels, the heater raising the
temperature of at least one of the plurality of conductance
channels relative to another one of the plurality of conductance
channels.
48. The deposition source of claim 42 wherein the heat shield
provides thermal isolation for at least one of the plurality of
conductance channels.
Description
RELATED APPLICATION SECTION
[0001] This application claims priority to both U.S. Provisional
Patent Application Ser. No. 61/156,348 filed Feb. 27, 2009,
entitled "Deposition Sources, Systems, and Related Methods for
Co-Depositing Copper, Indium, and Gallium," and U.S. Provisional
Application Ser. No. 61/138,932 filed Dec. 18, 2008, entitled
"Deposition Sources, Systems, and Related Methods for Co-Depositing
Copper, Indium, and Gallium." The entire specification of U.S.
Provisional Application Ser. No. 61/156,348 and U.S. Provisional
Application Ser. No. 61/138,932 are incorporated herein by
reference.
[0002] The section headings used herein are for organizational
purposes only and should not to be construed as limiting the
subject matter described in the present application in any way.
INTRODUCTION
[0003] Large area substrate deposition systems have been used for
processing flexible web substrates and rigid panel substrates of
numerous types of substrate materials for many years. Many known
systems are designed to process plastic web substrates and rigid
panel glass substrates. The web substrates or rigid panels are
passed directly above a linear deposition source. Known linear
deposition sources that are suitable for evaporating materials on a
web substrate or on a rigid panel substrate include a boat-shaped
crucible, which is typically formed of a refractory material for
containing deposition source materials. The crucible is placed in
the interior of a vapor outlet tube. The vapor outlet tube
functions simultaneously as a vaporizing space and as a space to
distribute the vapors. One or more vapor outlet openings are
arranged linearly along the source.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] The present teaching, in accordance with preferred and
exemplary embodiments, together with further advantages thereof, is
more particularly described in the following detailed description,
taken in conjunction with the accompanying drawings. The skilled
person in the art will understand that the drawings, described
below, are for illustration purposes only. The drawings are not
necessarily to scale, emphasis instead generally being placed upon
illustrating principles of the teaching. The drawings are not
intended to limit the scope of the teachings in any way.
[0005] FIG. 1 illustrates a perspective cross-sectional view of a
linear deposition source according to the present invention that
includes a plurality of crucibles coupled to a plurality of
conductance channels and then to a plurality of nozzles in a linear
configuration.
[0006] FIG. 2A illustrates a cross-sectional view of the linear
deposition source according to the present invention with the
plurality of nozzles positioned so that they evaporate deposition
material in an upward direction.
[0007] FIG. 2B illustrates a cross-sectional view of a linear
deposition source according to the present invention with the
plurality of nozzles positioned so that they evaporate deposition
material in a downward direction.
[0008] FIG. 2C illustrates a cross-sectional view of a linear
deposition source according to the present invention with the body
including the plurality of nozzles positioned in a vertical
direction.
[0009] FIG. 2D illustrates a cross-sectional view of another linear
deposition source according to the present invention with the body
including the plurality of nozzles positioned in a vertical
direction.
[0010] FIG. 3 illustrates a perspective cross-sectional view of a
linear deposition source according to the present invention that
includes a single crucible coupled to a plurality of conductance
channels and then to a plurality of nozzles in a linear
configuration.
[0011] FIG. 4 illustrates a perspective cross-sectional view of a
crucible for the linear deposition source of the present teaching
that is formed of two types of materials.
[0012] FIG. 5 illustrates a perspective top view of a portion of
the linear deposition source according to the present invention
that shows the three conductance channels coupled to three
crucibles in the housing.
[0013] FIG. 6A is a perspective view of a portion of a resistive
crucible heater for the linear deposition source of the present
invention that shows the inside and three sides of the heater where
the crucible is positioned.
[0014] FIG. 6B is a perspective view of an outside of one of the
plurality of crucible heaters for heating each of the plurality of
crucibles.
[0015] FIG. 7A is a side view of a linear deposition source
according to the present invention that shows conductance channel
heaters for heating the plurality of conductance channels.
[0016] FIG. 7B is a perspective view of the rods comprising the
conductance channel heaters.
[0017] FIG. 7C illustrates a perspective view of the body of a
linear deposition source according to the present invention that
shows a coupling which joins the end of the rods to the body.
[0018] FIG. 8 illustrates the frame of the body that includes an
expansion link.
[0019] FIG. 9A is a perspective cross-sectional view of a heat
shield for the plurality of crucibles and for the plurality of
conductance channels of a linear deposition source according to the
present teaching.
[0020] FIG. 9B is a full perspective view of the heat shield shown
in FIG. 9A.
[0021] FIG. 10 illustrates a top perspective view of a deposition
source according to the present teaching that shows the plurality
of nozzles in the body for emitting evaporated materials onto
substrates or other workpieces.
[0022] FIG. 11A illustrates a cross-sectional view of the body of
the deposition source according to the present teaching that shows
a column of nozzles coupled to a conductance channel with tubes
that control the flow of deposition material to the nozzles.
[0023] FIG. 11B illustrates a cross-sectional view of the plurality
of conductance channels of the deposition source according to the
present teaching that shows a row of nozzles coupled to the
plurality of conductance channel with tubes that control the flow
of deposition material to the nozzles.
[0024] FIG. 12 illustrates a perspective view of a nozzle
comprising one of the plurality of nozzles for a linear deposition
source according to the present teaching.
DESCRIPTION OF VARIOUS EMBODIMENTS
[0025] Reference in the specification to "one embodiment" or "an
embodiment" means that a particular feature, structure, or
characteristic described in connection with the embodiment is
included in at least one embodiment of the teaching. The
appearances of the phrase "in one embodiment" in various places in
the specification are not necessarily all referring to the same
embodiment.
[0026] It should be understood that the individual steps of the
methods of the present teachings may be performed in any order
and/or simultaneously as long as the teaching remains operable.
Furthermore, it should be understood that the apparatus and methods
of the present teachings can include any number or all of the
described embodiments as long as the teaching remains operable.
[0027] The present teaching will now be described in more detail
with reference to exemplary embodiments thereof as shown in the
accompanying drawings. While the present teaching is described in
conjunction with various embodiments and examples, it is not
intended that the present teaching be limited to such embodiments.
On the contrary, the present teaching encompasses various
alternatives, modifications and equivalents, as will be appreciated
by those of skill in the art. Those of ordinary skill in the art
having access to the teaching herein will recognize additional
implementations, modifications, and embodiments, as well as other
fields of use, which are within the scope of the present disclosure
as described herein.
[0028] The present teaching relates generally to apparatus and
methods for producing a flux of source material vapor for
deposition on a substrate. Some aspects of the present teaching
relate to linear deposition sources that are suitable for producing
a flux of source material vapor for depositing material on a web
substrate, a rigid panel substrate, or another type of an elongated
workpiece. Other aspects of the present teaching relate to linear
deposition sources that are suitable for producing a flux of source
material vapor for depositing material on a substrate holder that
supports a plurality of conventional substrates, such as
semiconductor substrates.
[0029] In many embodiments of the present teaching, the methods and
apparatus relate to deposition by evaporation. The term
"evaporation" as used herein means to convert the source material
to a vapor and includes the normal use of several terms in the art,
such as evaporation, vaporization, and sublimation. The source
material being converted to a vapor can be in any state of matter.
In many embodiments, the apparatus and method of the present
teaching are used to co-evaporate two or more different materials
onto a substrate, such as a web substrate or a rigid panel
substrate. In some embodiments, the apparatus and method of the
present teaching are used to evaporate a single material onto a
substrate, such as a web substrate or a rigid panel substrate.
[0030] One application of the present teaching relates to methods
and apparatus for co-deposition of copper, indium, and gallium onto
a web substrate or a rigid panel substrate. Compounds of copper
indium diselenide (CIS compounds) that have gallium substituted for
all or part of the indium are known as copper indium gallium
diselenide compounds (CIGS compounds). CIGS compounds are commonly
used to fabricate photovoltaic cells. In particular, CIGS compounds
are commonly used as absorber layers in thin-film solar cells.
These CIGS compounds have a direct band gap which permits strong
absorption of solar radiation in the visible region of the
electromagnetic spectrum. CIGS photovoltaic cells have been
demonstrated to have high conversion efficiencies and good
stability as compared to commonly used photovoltaic cells with
other types of absorber layer compounds, such as cadmium telluride
(CdTe) and amorphous silicon (a-Si).
[0031] CIGS absorbing layers are typically p-type compound
semiconductor layers with good crystallinity. Good crystallinity is
generally required to achieve desired charge transport properties
necessary for high efficiency photovoltaic operation. In practice,
the CIGS absorbing layer must be at least partially crystallized in
order to achieve high efficiency photovoltaic operation.
Crystallized CIGS compounds have a crystallographic structure which
can be characterized as either chalcopyrite or sphalerite depending
on the deposition temperature used to form the CIGS compound.
[0032] CIGS compounds can be formed by various techniques. One
method for forming CIGS compounds uses chemical precursors. The
chemical precursors are deposited in thin films and are then
subsequently annealed to form the desired CIGS layer. When CIGS
precursor materials are deposited at a low temperature, the
resulting CIGS thin films are amorphous or only weakly
crystallized. The CIGS thin films are then annealed at elevated
temperatures to improve the crystallization of the CIGS compound in
order to provide the desired charge transport properties.
[0033] However, at the elevated temperatures necessary to cause
partial crystallization of the CIGS thin films, the selenium in the
deposited thin film is more volatile than the other elements.
Consequently, selenium is often added while annealing the precursor
layers to improve crystallized and to provide the CIGS compound
with the desired composition and stoichiometry. This method of
forming CIGS thin film compounds is relatively time consuming and
requires large volumes of selenium in the vapor phase, which adds
to the manufacturing costs.
[0034] Another method for forming CIGS compounds uses vacuum
evaporation. CIGS photovoltaic cells fabricated by co-evaporation
can have high photovoltaic conversion efficiencies compared to CIGS
photovoltaic cells fabricated with precursor materials. In this
method, copper, indium, gallium, and selenium are co-evaporated
onto a substrate. Co-evaporation allows for precise control of the
thin film stoichiometry and allows for compositional grading in the
thin film light-absorbing layer. Therefore, co-evaporation can be
used to precisely tailor the bandgap in order to achieve optimum
photovoltaic performance. However, co-evaporation of copper,
indium, gallium, and selenium is a process technique that can be
difficult to use on an industrial scale because it is difficult to
evaporate materials uniformly over large surface areas.
[0035] One aspect of the present teaching is to provide deposition
sources, systems, and methods of operating such sources and systems
to efficiently and controllably provide multiple vaporized source
materials for fabrication of numerous types of devices, such as
CIGS photovoltaic cells. Another aspect of the present teaching is
to provide deposition sources, systems, and methods of operating
such sources and systems to efficiently and controllably provide a
single vaporized source material for fabrication of numerous types
of devices, such as organic light-emitting diode (OLED) devices.
One skilled in the art will appreciate that although some aspects
of the present teachings are described in connection with the
fabrication of CIGS photovoltaic cells and OLED devices, the
teachings in this disclosure apply to any other type of device that
can be fabricated using evaporated materials.
[0036] FIG. 1 illustrates a perspective cross-sectional view of a
linear deposition source 100 according to the present invention
that includes a plurality of crucibles 102 coupled to a plurality
of conductance channels 104 and then to a plurality of nozzles 106
in a linear configuration. Each of the plurality of crucibles 102
contains an evaporation source material, which may be the same or a
different source material. An input of each of the plurality of
conductance channels 104 is coupled to an output of a respective
one of the plurality of crucibles 102. In many embodiments, the
plurality of conductance channels 104 is designed so that there is
no intermixing of evaporated materials while the evaporated
materials are being transported in the plurality of conductance
channels 104.
[0037] A housing 108 contains the plurality of crucibles 102. The
housing 108 is formed of stainless steel or a similar material. In
some embodiments, fluid cooling channels are positioned along the
housing 108. The housing 108 also includes a sealing flange 110
that attaches the housing 108 to a vacuum chamber (not shown). One
feature of the linear deposition source 100 is that the crucibles
are outside of the vacuum chamber and, therefore, they are easily
refilled and serviced, thereby increasing availability. A body 112
including the plurality of conductance channels 104 and the
plurality of nozzles 102 extends past the sealing flange 110 of the
housing 108. In some embodiments, fluid cooling channels are
positioned along the body 112.
[0038] In the embodiment shown in FIG. 1, the source 100 includes
three crucibles 102 in a linear configuration with inputs of
respective ones of the three conductance channels 104 being coupled
to outputs of respective ones of the three crucibles 102. The
nozzles 106 are positioned at a plurality of locations along each
of the plurality of conductance channels 104. However, because FIG.
1 is a cross-sectional view, only the middle conductance channel
104, and one half the nozzles 106 are shown in FIG. 1.
[0039] One skilled in the art will appreciate that numerous types
of crucibles can be used. For example, at least some of the
plurality of crucibles can include at least one crucible formed
inside another crucible as described in connection with FIG. 4. The
plurality of crucibles 102 contains evaporation material suitable
for the particular fabrication process. In many embodiments, each
of the plurality of crucibles 102 contains a different evaporation
material. For example, each of the three crucibles can contain one
of copper, indium, and gallium so as to provide a material source
for efficiently co-evaporating a functional absorbing layer of a
CIGS based photovoltaic device. However, in some embodiments, at
least two of the plurality of crucibles contains the same
deposition material. For example, each of the three crucibles can
contain a single material system for depositing contacts for OLED
devices.
[0040] One or more crucible heaters 114 are positioned in thermal
communication with the plurality of crucibles 102. The crucible
heaters 114 are designed and positioned to increase the temperature
of the plurality of crucibles 102 so that each of the plurality of
crucibles 102 evaporates its respective deposition source material
into a respective one of the plurality of conductance channels 104.
Some crucible heaters 114 are required to heat the evaporation
source material to very high temperatures. Such crucible heaters
can be formed of graphite, silicon carbide, refractory materials,
or other very high melting point materials. The crucible heaters
114 can be one single heater or can be a plurality of heaters. For
example, in one embodiment, each of a plurality of crucible heaters
is individually controllable so that a respective one of the
plurality of crucible heaters is in thermal communication with a
respective one of each of the plurality of crucibles 102.
[0041] The crucible heaters 114 can be any type of heater. For
example, the crucible heaters 114 can be resistive heaters as shown
in FIG. 1. One embodiment of a resistive heater is described in
more detail in connection with FIGS. 6A and 6B. The crucible
heaters 114 can also be one of numerous types of RF induction
heaters and/or infrared heaters. In many embodiments, all the
crucible heaters 114 are the same type of heater. However, in some
embodiments, two or more of the crucible heaters 114 are different
types of heaters that have different thermal properties for
evaporating different deposition source materials.
[0042] The crucible heaters 114 or separate conductance channel
heaters are positioned in thermal communication with at least one
of the plurality of conductance channels 104 so that the
temperature of each of the plurality of conductance channels 104 is
raised above the condensation point of deposition source materials
passing through the particular conductance channel. Conductance
channel heaters are described in connection with FIGS. 7A, 7B and
7C. One skilled in the art will appreciate that numerous types of
heaters can used to heat the plurality of conductance channels 104,
such as resistive heaters, RF induction heaters, and/or infrared
heaters. The conductance channel heater can be a single heater or
can be a plurality of heaters. More than one type of heater can be
used. In one embodiment, the conductance channel heater has the
capability of controlling a temperature of one of the plurality of
conductance channels 104 relative to another one of the plurality
of conductance channels 104.
[0043] FIG. 2A illustrates a cross-sectional view of the linear
deposition source 100 according to the present invention with the
plurality of nozzles 106 positioned so that they evaporate
deposition material in an upward direction. One feature of the
linear deposition source of the present teaching is that the
plurality of nozzles 106 can be positioned in any orientation
relative to the plurality of crucibles 102. The heater for the
plurality of conductance channels 104 is designed to prevent the
evaporated source material from condensing independent of the
orientation of the plurality of nozzles 106.
[0044] FIG. 2B illustrates a cross-sectional view of a linear
deposition source 150 according to the present invention with the
plurality of nozzles 106 positioned so that they evaporate
deposition material in a downward direction. The linear deposition
source 150 of FIG. 2B is similar to the linear deposition source
100 described in connection with FIG. 2A. However, the plurality of
nozzles 106 is positioned with their outlet apertures facing
downward in the direction of the plurality of crucibles 102.
[0045] FIG. 2C illustrates a cross-sectional view of a linear
deposition source 152 according to the present invention with the
body 112' including the plurality of nozzles 106 positioned in a
vertical direction. The linear deposition source 152 is similar to
the linear deposition source 100 described in connection with FIG.
2A except that the linear deposition source 152 includes an angled
coupling 154 that changes the orientation of the body 112' relative
to the normal direction from the sealing flange 110. One skilled in
the art will appreciate that the angled coupling 154 can position
the body 112' at any angle relative to the normal direction of the
sealing flange 110. Thus, one feature of the linear deposition
source of the present teaching is that the body 112' including the
plurality of nozzles 106 can be positioned in any orientation
relative to the housing 108 comprising the plurality of crucibles
102. The heater for the plurality of conductance channels 104 (FIG.
1) is designed to prevent the evaporated source material from
condensing independent of the orientation of the body 112'.
[0046] FIG. 2D illustrates a cross-sectional view of another linear
deposition source 156 according to the present invention with the
body 112'' including the plurality of nozzles 106 positioned in a
vertical direction. The linear deposition source 156 is similar to
the linear deposition source 152 described in connection with FIG.
2C except that the linear deposition source 156 includes a T-shaped
coupling 158 that changes the orientation of the body 112''
relative to the normal direction from the sealing flange 110. In
the embodiment shown in FIG. 2D, the body 112'' extends in the
vertical direction on both sides of the T-shaped coupling 158.
[0047] FIG. 3 illustrates a perspective cross-sectional view of a
linear deposition 200 source according to the present invention
that includes a single crucible 202 coupled to a plurality of
conductance channels 204 and then to a plurality of nozzles 206 in
a linear configuration. The linear deposition source 200 is similar
to the linear deposition source 100 that is described in connection
with FIGS. 1 and 2. However, the source 200 includes only one
crucible 202. The single crucible 202 is positioned in a housing
208 as described in connection with FIG. 1.
[0048] The single crucible 202 can have a single compartment that
is designed for one type of deposition source material. Such a
crucible coupled to the plurality of conductance channels 204 will
have relatively high deposition flux throughput. Alternatively, the
single crucible 202 can have a plurality of partitions 210 that
partially isolate sections of the crucible 202 where each of the
partially isolated sections is dimensioned for positioning one of a
plurality of deposition source materials. The plurality of
deposition source materials can be the same material or can be a
different material. In embodiments where the single crucible 202
includes a plurality of partially isolated sections, an input of
each of the plurality of conductance channels 204 is positioned
proximate one of the plurality of partially isolated sections.
[0049] A heater 212 is positioned in thermal communication with the
single crucible 202. The heater 212 increases the temperature of
the crucible 202 so that the crucible evaporates the at least one
deposition material into the plurality of conductance channels 204.
The heater 212 or a second heater is positioned in thermal
communication with at least one of the plurality of conductance
channels 204 in order to raise the temperature of the plurality of
conductance channels 204 so that evaporated deposition source
materials do not condense. Some heaters 212 can raise the
temperature of at least one of the plurality of conductance
channels 204 relative to another one of the plurality of
conductance channels 204.
[0050] A heat shield 214 is positioned proximate to the crucible
202 and to the plurality of conductance channels 204 to provide at
least partial thermal isolation of the crucible 202 and of the
plurality of conductance channels 204. In some embodiments, the
heat shield 214 is designed and positioned to control the
temperature of one section of the crucible 202 relative to another
section of the crucible 202. Also, in some embodiments, the heat
shield 214 is designed and positioned in order to provide at least
partial thermal isolation of at least one of the plurality of
conductance channels 204 relative to at least one other conductance
channels 204 so that different temperatures can be maintained in at
least two of the plurality of conductance channels 204. In this
embodiment, at least two of the plurality of conductance channels
204 can be shielded with heat shielding material having different
thermal properties.
[0051] The plurality of nozzles 206 are coupled to the plurality of
conductance channels 204. Evaporated deposition materials are
transported from the single crucible 202 through the plurality of
conductance channels 204 to the plurality of nozzles 206 where the
evaporated deposition material is ejected from the plurality of
nozzles 206 to form a deposition flux.
[0052] The linear sources of the present teaching are well suited
for evaporating one or more different deposition source materials
on large area workpieces, such as web substrates and rigid panel
substrates. The linear geometry of the sources makes them well
suited for processing wide and large area workpieces, such as web
substrates and rigid panel substrates used for photovoltaic cells
because the source can provide efficient and highly controllable
vaporized material over a relatively large area.
[0053] One feature of the linear deposition sources of the present
teaching is that they are relatively compact. Another feature of
the linear deposition sources of the present teaching is that they
uses common heaters and common heat shielding materials for each
the plurality of deposition sources and for each of the plurality
of conductance channels, which improves many equipment performance
metrics, such as the size, equipment cost, and operating costs.
[0054] FIG. 4 illustrates a perspective cross-sectional view of a
crucible 300 for the linear deposition source of the present
teaching that is formed of two types of materials. The crucible 300
includes at least one crucible positioned inside another crucible.
In the embodiment shown in FIG. 2, the crucible 300 includes an
inner crucible 302 nested inside an outer crucible 304. In this
crucible design, two types of materials can be used to contain the
deposition material in order to improve the performance of the
crucible. In other embodiments, at least one crucible is nested
inside at least two other crucibles.
[0055] For example, in one embodiment, one or more of the plurality
of crucibles 102 (FIG. 1) or crucible 202 (FIG. 3) is constructed
with the inner crucible 302 formed of pyrolytic boron nitride and
the outer crucible 304 formed of graphite. In this embodiment, the
inner crucible 302 formed of the pyrolytic boron nitride contains
the deposition source material. Pyrolytic boron nitride is a
non-porous, highly inert, and an exceptionally pure material. In
addition, pyrolytic boron nitride has a very high melting point,
good thermal conductivity, and excellent thermal shock properties.
These properties make pyrolytic boron nitride very well suited for
directly containing most evaporation source materials. However,
pyrolytic boron nitride is particularly brittle and, therefore, is
easily damaged. The outer crucible 304 is formed of a material,
such as graphite that is more durable, but still capable of high
temperature operation. The more durable material protects the
pyrolytic boron nitride from damage. In another embodiment, the
inner crucible is formed of quartz and the outer crucible is formed
of alumina. The combination of a quartz inner crucible and an
alumina outer crucible is relatively inexpensive.
[0056] FIG. 5 illustrates a perspective top view of a portion of
the linear deposition source 100 according to the present invention
that shows the three conductance channels 104 coupled to three
crucibles 102 in the housing 108. An input 118 of each of the three
conductance channels 104 is coupled to an output of a respective
one of the three crucibles 102. The three conductance channels 104
are designed so that there is no significant intermixing of
evaporated materials from any of the three crucibles 102 while the
evaporated materials are being transported through the plurality of
conductance channels 104. In many deposition processes, it is
important to substantially prevent intermixing of deposition
materials in order to prevent reactions of two or more deposition
materials from occurring before the deposition material reaches the
surface of the substrate being processed.
[0057] FIG. 6A is a perspective view of a portion of a resistive
crucible heater 400 for the linear deposition source of the present
invention that shows the inside and three sides of the crucible
heater 400 where the crucible 102 (FIG. 1) is positioned. In
various embodiments, the crucible heater 400 can be fixed in the
housing 108 (FIG. 1) or can removably attached to the housing 108.
The crucible heater 400 includes a plurality of resistive heating
elements 402 on the bottom and sides that surround the crucible
102. In the embodiment shown in FIG. 6A, the resistive heating
elements 402 are a plurality of spaced apart graphite bus bars 402
that are linear strips of graphite material. Support rods 404
structurally connect the graphite bus bars 402 together and also
electrically insulating the bus bars 402. The resistive heating
elements 402 can include serpentine graphite springs positioned
between opposite ends of the heating elements 402. Electrical wires
are fed through the housing 108 of the source 100 to connect the
graphite bus bars 402 to a power supply (not shown). The graphite
bus bars 402 include screws 406 for securely attaching the
electrical wires.
[0058] FIG. 6B is a perspective view of an outside of one of the
plurality of crucible heaters 400 for heating each of the plurality
of crucibles 102 (FIG. 1). The perspective view shown in FIG. 6B is
similar to the perspective view shown in FIG. 6A, but it shows all
four sides of the crucible heater 400.
[0059] FIG. 7A is a side view of a linear deposition source 100
according to the present invention that shows conductance channel
heaters for heating the plurality of conductance channels 104 (FIG.
1). FIG. 7B shows a perspective view of the rods 130 comprising the
conductance channel heaters. FIG. 7C illustrates a perspective view
of the body 112 of a linear deposition source 100 according to the
present invention that shows a coupling 132 which joins the end of
the rods 130 to the body 112.
[0060] Referring to FIGS. 1, 7A, 7B, and 7C, the rods 130 are
positioned proximate to the conductance channels 104 in the
longitudinal direction of the body 112 along the length of the
conductance channels 104. The rods 130 can be formed of any type of
high temperature resistive material such as graphite, silicon
carbide, refractory materials, or other very high melting point
materials. The rods 130 are electrically connected to an output of
a power supply (not shown) that generates a current which flows
through the rods 130, thereby increasing the temperature of the
rods 130. The rods 130 can be electrically connected to the output
of the power supply using a spring or a wire harness that provides
for enough movement to allow for thermal expansion of the rods 130
during normal operation. Heat generated in the rods 130 by current
from the power supply radiates into the conductance channels 104,
thereby raising the temperature of the conductance channels 104 so
that evaporated source material transporting through the plurality
of conductance channels 104 does not condense.
[0061] FIG. 7A also shows a plurality of coupling 152 that attach
segments of the rods 130 together. In some embodiments, the length
of the body 112 is so long that coupling multiple segments of rods
130 together is more cost effective, reliable, and easier to
manufacture. One skilled in the art will appreciate that there are
numerous types of couplings that can be used to couple together
multiple segments of rods 130. For example, a threaded coupling can
be used to couple two rod segments together. The coupling 132
provide a continuous electrical connection with a relatively
constant resistance through the entire length of the rods 130.
[0062] FIG. 8 illustrates the frame 500 of the body 112 (FIG. 1)
that includes an expansion link 502. Referring to FIGS. 1, 7A, and
8, the plurality of conductance channels 104 is removed from the
space inside the frame 500 of the body 112 in order to view the
expansion link 502. The expansion link 502 is sometimes used
because the body 112 experiences significant thermal expansion and
contraction during normal operation. The coefficient of thermal
expansion of the rods 130 and the plurality of conductance channels
104 can be significantly different from the coefficient of thermal
expansion of the frame 500 and other components in the body 112. In
addition, there may be significant temperature differences between
the frame 500 and other components in the body 112, such as the
rods 130 and the plurality of conductance channels 104.
Consequently, it is desirable for the frame 500 to expand and
contract freely relative to other components in the body 112, such
as the plurality of conductance channels 104 and the rods 130.
[0063] The expansion link 500 shown in FIG. 8 is one of numerous
types of expansion links that can be used in the frame 500. In the
embodiment shown in FIG. 8, the expansion link 500 is attached to
two sections of the frame 500 with pins 504 or other types of
fasteners. When the expansion link 502 is expanded, the linking
section 506 expands, thereby creating space in the frame 500 for
components in the body 112 that are expanding faster than the frame
500. Alternatively, when components in the body 112 are contracting
faster than the frame 500, the linking section 506 folds, thereby
reducing space in the frame 500 to match the space of the
contracting body 112.
[0064] FIG. 9A is a perspective cross-sectional view of a heat
shield 600 for the plurality of crucibles 102 (FIG. 1) and for the
plurality of conductance channels 104 of a linear deposition source
according to the present teaching. FIG. 9B is a full perspective
view of the heat shield 600 shown in FIG. 9A. One skilled in the
art will appreciate that the heat shield 600 can be made of any one
of numerous types of heat shielding material. For example, in one
embodiment, the heat shield 600 is formed of a carbon fiber carbon
composite material.
[0065] Referring to FIGS. 1, 9A and 9B, a first section 602 of the
heat shield 600 is positioned proximate to each of the plurality of
crucibles 102 in order to provide at least partial thermal
isolation of each of the plurality of crucibles 102. The first
section 602 of the heat shield 600 isolates the individual
crucibles 102 so that significantly different crucible temperatures
can be maintained during processing if necessary. Maintaining
significantly different crucible temperatures is important for some
deposition processes because each of the plurality of crucibles 102
can then be heated to its optimum temperature for the particular
source material. Heating the crucibles 102 to their optimum
temperature for the particular source material reduces negative
heating effects, such as spitting of deposition material. In
addition, heating the crucibles 102 to their optimum temperature
for the particular source material can significantly reduce the
operating costs of the deposition source.
[0066] In various other embodiments, the first section 602 of the
heat shield 600 can include a plurality of separate heat shields
where a respective one of the plurality of separate heat shields
600 surrounds a respective one of the plurality of crucibles 102.
Each of the plurality of separate heat shields can be the same or
can be a different heat shield. For example, crucibles that are
used to heat higher temperature deposition source materials can be
formed of different or thicker heat shielding materials with
different thermal properties.
[0067] The second section 604 of the heat shield 600 is positioned
proximate to the plurality of conductance channels 104 in order to
provide at least partial thermal isolation of the plurality of
conductance channels 104 from the plurality of crucibles 102. Each
of the plurality of conductance channels 104 can be shielded by a
separate heat shield or a single heat shield can be used. In some
embodiments, the second section 604 of the heat shield 600 is
positioned in order to provide at least partial thermal isolation
of at least one of the plurality of conductance channels 104
relative to at least one other conductance channel. In other words,
the design and positioning of the second section 604 of the heat
shield 600 can be chosen to allow a different operating temperature
in at least one of the plurality of conductance channels 104
relative to at least one other of the plurality of conductance
channels 104. In these embodiments, at least two of the plurality
of conductance channels 104 can be shielded with heat shielding
material having different thermal properties. For example, at least
two of the plurality of conductance channels 104 can be shielded by
different heat shielding materials, different heat shielding
thickness, and/or different proximities of the heat shielding
material to particular conductance channels.
[0068] The heat shield 600 is exposed to very high temperatures
during normal operation. Some heat shields according to the present
teachings are constructed with at least one surface being formed of
a low emissivity material or having a low emissivity coating that
reduces the emission of thermal radiation. For example, an inner or
outer surface of the heat shield 600 can be coated with a low
emissivity coating or any other type of coating that reduced heat
transfer. Any such coating is usually designed to maintain constant
emissivity over the operational lifetime of the source.
[0069] The heat shield 600 also expands and contracts at different
rates compared to the housing 108 and the body 112 and to
components in the housing 108 and body 112. In one embodiment, the
heat shield 600 is movably attached to at least one of the housing
108 and the frame 500 (FIG. 8) of the body 112 so that it can move
relative to at least one of the housing 108 and the frame 500
during normal operation. In some embodiments, an expansion link is
used to allow the heat shield 600 to expand and contract relative
to other source components. Furthermore, in some embodiments, the
heat shield 600 includes a plurality of layers of heat shielding
materials that are tolerant to thermal expansion and contraction.
For example, a plurality of heat shielding tiles can be used to
increase the tolerance to thermal expansion and contraction.
[0070] FIG. 10 illustrates a top perspective view of a deposition
source 100 according to the present teaching that shows the
plurality of nozzles 106 in the body 112 for emitting evaporated
materials onto substrates or other workpieces. An input of each of
the plurality of nozzles 106 is coupled to an output of a
respective one of the plurality of conductance channels 104 as
described in connection with FIG. 5. The evaporated deposition
materials are transported without intermixing from the plurality of
crucibles 102 through the plurality of conductance channels 104 to
the plurality of nozzles 106 where the evaporated deposition
material is ejected from the plurality of nozzles 106 to form a
deposition flux.
[0071] The source 100 shown in FIG. 10 illustrates seven groups of
nozzles 106 where each group includes three nozzles. One skilled in
the art will appreciate that a deposition source according to the
present invention can include any number of groups of nozzles and
any number of nozzles within each group. In various embodiments,
the spacing of the plurality of nozzles 106 can be uniform or
non-uniform. One aspect of the present teaching is that the
plurality of nozzles 106 can be non-uniformly spaced in order to
achieve certain process goals. For example, in one embodiment, the
spacing of the plurality of nozzles 106 is chosen to improve
uniformity of the deposition flux. In this embodiment, the spacing
of the nozzles 106 near the edge of the body 112 is closer than the
spacing of the nozzles 106 proximate to a center of the body 112 as
shown in FIG. 10 in order to compensate for reduced deposition flux
near the edges of the body 112. The exact spacing can be chosen so
that the source 100 generates a substantially uniform deposition
material flux proximate to the substrate or workpiece.
[0072] In some embodiments, the spacing of the plurality of nozzles
106 is chosen to obtain high material utilization in order to lower
the operating cost of the deposition source 100 and to increase the
process time and availability between service intervals. Also, in
some embodiments, the spacing of the plurality of nozzles 106 is
chosen to provide a desired overlap of deposition flux from the
plurality of nozzles 106 in order to achieve a predetermine mixture
of evaporated materials.
[0073] In one embodiment, at least some of the plurality of nozzles
106 is positioned at an angle relative to the normal angle from the
top surface 160 of the conductance channels 104 in order to achieve
certain process goals. For example, in one embodiment, at least one
of the plurality of nozzles 106 is positioned at an angle relative
to the normal angle from the top surface 160 of the conductance
channels 104 that is chosen to provide a uniform deposition flux
across the surface of the substrates or workpieces being processed.
Also, in some embodiments, at least one of the plurality of nozzles
106 is positioned at an angle relative to the normal angle from the
top surface 160 of the conductance channels 104 that is chosen to
provide a desired overlap of deposition flux from the plurality of
nozzles 106 to achieve a predetermine mixture of evaporated
materials.
[0074] FIG. 11A illustrates a cross-sectional view of the body 112
of the deposition source 100 according to the present teaching that
shows a column of nozzles 106 coupled to a conductance channel 104
with tubes 170 that control the flow of deposition material to the
nozzles 104. In some embodiments, the emissivity at the top of the
tubes 170 is lower than the emissivity at the bottom of the tubes
170. The dimensions of the tubes 170, such as the length and
diameter of the tubes 170, determine the amount of deposition
material that is supplied from the conductance channel 104 to the
corresponding nozzles 106. In addition, the positioning of the
tubes 170, such as the distance that the tubes 170 are positioned
in the conductance channel 104, also determines the amount of
deposition material that is supplied from the conductance channel
104 to the corresponding nozzle 106.
[0075] For example, changing the diameter of the tubes 170 changes
the distribution deposition flux pattern emanating from the nozzle
106. The length of the tubes 170 is generally chosen to match the
overall flow resistance and design of the tubes 170. In some
embodiments, longer tubes 170 that penetrate further into the
conductance channel 104 will supply less deposition material to the
corresponding nozzle 106. In various embodiments, the geometry and
position of particular tubes 170 can be the same or can be
different. In one embodiment, at least two of the plurality of
tubes 170 can have different lengths and/or different geometries in
order to obtain a particular conductance through each of the
plurality of tubes 170 that achieves certain process goals. For
example, tubes 170 with different dimensions can be used to
compensate for pressure differentials in the source 100 from the
body 112 near the sealing flange 110 to the end of the body
112.
[0076] Thus, one feature of the deposition source 100 of the
present invention is that the geometry and positioning of the tubes
170 can be chosen to precisely control the quantity of evaporated
material supplied to each of the plurality of nozzles 106 without
changing the distribution of the evaporated material emanating from
the plurality of nozzles 106. For example, a geometry and position
of particular tubes 170 can be chosen to achieve certain process
goals, such as a predetermined deposition flux from particular
nozzles or from the plurality of nozzles 106.
[0077] In some embodiments, at least one of the plurality of
nozzles 106 extends above the top surface 160 of the plurality of
conductance channels 104 in order to prevent vapor condensation and
material accumulation building up over time. Nozzles can also be
positioned to achieve a desired deposition flux distribution
pattern. Individual nozzle heaters can be positioned proximate to
one or more of the plurality of nozzles 106 to control the
temperature of the vaporized material emanating from the nozzles
106 to prevent condensation and material accumulation. In other
embodiments, at least one of the plurality of nozzles 106 is
positioned below the top surface 160 of the plurality of
conductance channels 104 in order to conduct the desired amount of
heat from the heater and the plurality of conductance channels 104
and/or to achieve a desired deposition flux distribution
pattern.
[0078] FIG. 11B illustrates a cross-sectional view of the plurality
of conductance channels 104 of the deposition source 100 according
to the present teaching that shows a row of nozzles 106 coupled to
the plurality of conductance channel 104 with tubes 170 that
control the flow of deposition material to the nozzles 104. FIG.
11B shows three conductance channels with tubes. One aspect of the
present teachings is that the nozzles 106 are heated by the
conductance channel heaters (rods 130 in FIGS. 7A-C) and by the
associated conductance channel 104.
[0079] FIG. 12 illustrates a perspective view of a nozzle 106
comprising one of the plurality of nozzles 106 for the linear
source 100 according to the present teaching. The nozzle 106 is
designed so that it provides the required heat conduction to
prevent the evaporated source material from condensing. The nozzle
106 can be formed of a material having a thermal conductivity that
results in a uniform operating temperature, thereby reducing
spitting of deposition materials. For example, the nozzle can be
formed of graphite, silicon carbide, a refractory material, or
other very high melting point materials. In some embodiments, the
nozzle 106 is designed to reduce thermal gradients through the
nozzle 106. In addition, the nozzle 106 can be designed to minimize
radiation losses.
[0080] In some embodiments, the nozzle 106 can include a tapered
outside surface. Also, in some embodiments, the nozzle 106 is
tapered on the inside. In some embodiments, the surface of the
aperture 180 has a low emissivity coating that reduces thermal
emission, thereby reducing any condensation in the nozzle 106. In
other embodiments, the nozzle 106 is formed of a material with a
low emissivity.
[0081] The nozzle 106 includes an aperture 180 for passing the
evaporated source material from the associated conductance channel
104. The aperture 180 is designed to eject the desired plume. A
generally round aperture 108 is shown in the nozzle 106 of FIG. 12.
However, it should be understood that any one of numerous aperture
shapes can be used in the nozzle 106 to achieve the desired
processing goals. For example, the aperture 180 can be round, oval,
rectangle, square, or a slit. In addition, the outlet of the
aperture 180 is shown with a radius shape. However, it should be
understood that the aperture 180 can use any one of numerous outlet
shapes to achieve the desired processing goals. For example, the
outlet shape can be chamfered, radiused or sumo style (i.e. reverse
draft or other type of restricted nozzle shape).
[0082] In some embodiments, at least one of the plurality of
nozzles 106 has an aperture 180 that is shaped to pass a
non-uniform deposition flux. In these embodiments, at least some of
the plurality of apertures 180 can be shaped to pass non-uniform
deposition flux that combines to form a desired deposition flux
pattern. For example, the desired combined deposition flux pattern
can be a uniform deposition flux pattern over a predetermined
area.
[0083] In operation, a method of generating deposition flux from
multiple deposition sources includes heating a plurality of
crucibles 102 that each contains a deposition source material so
that each of the plurality of crucibles 102 evaporates deposition
material. The method can include independently controlling separate
crucible heaters to achieve different crucible temperatures for
each deposition source material. The method can also include
shielding each of the plurality of crucibles 102 so that different
temperatures can be maintained in particular crucibles.
[0084] Deposition material from each of the plurality of crucibles
102 transports through respective conductance channels 104 in the
body 112 without intermixing the deposition materials evaporated
from any of plurality of crucibles 102. The conductance channels
104 are heated so that the vaporized deposition material does not
condense before emanating from the nozzles 106. The conductance
channels 104 can be separately heated so as to achieve different
temperatures for at least two of the plurality of conductance
channels 104. Each of the plurality of conductance channels 104 can
be shielded so that different temperatures can be maintained in
different conductance channels 104. Many methods include providing
movable components and space for thermal expansion of heater and
heat shielding material proximate to the plurality of crucibles 102
and proximate to the plurality of conductance channels 104.
[0085] Evaporated deposition material is transported from each of
the plurality of conductance channels 104 to respective ones of the
plurality of nozzles 106. In various embodiments, the evaporated
deposition material is transported from each of the plurality of
conductance channels 104 to a respective one of the plurality of
nozzles 106 through a respective one of a plurality of tubes 170 or
other structures that control the flow of the deposition material.
In various embodiments of the method of the present invention, the
flow of the deposition material through the plurality of nozzles
106 is controlled by using tubes with varying length, geometry,
and/or position of the tube inlet relative to the conductance
channel 104. The length, geometry, and/or position of the tube
inlet relative to the conductance channel 104 are chosen to achieve
certain process goals such as uniform deposition flux and/or high
deposition material utilization.
[0086] The plurality of nozzles 106 then passes the evaporated
deposition material, thereby forming a deposition flux. The method
can include selecting a spacing of the plurality of nozzles 106 to
achieve certain process goals, such as uniform deposition flux from
the plurality of nozzles 106 and/or high deposition material
utilization.
EQUIVALENTS
[0087] While the applicant's teaching are described in conjunction
with various embodiments, it is not intended that the applicant's
teaching be limited to such embodiments. On the contrary, the
applicant's teaching encompass various alternatives, modifications,
and equivalents, as will be appreciated by those of skill in the
art, which may be made therein without departing from the spirit
and scope of the teaching.
* * * * *